Thallium complexes of tetraphenylporphyrin: Tl(tpp-N-O)(OAc) and cis-acetato-N-p-tert-butylbenzensulfonylimido-meso-tetraphenylporphyrinatothallium(III) Tl(N-p-NSO2C6H4tBu-tpp)(OAc)

Article abstract of DOI:10.1016/j.poly.2006.01.020

The crystal structures of Tl(tpp-N-O)(OAc) (3) and acetato-N-p-tert-butylbenzensulfonylimido-meso-tetraphenylporphyrinatothallium(III) Tl(N-p-NSO₂C₆H₄^tBu-tpp)(OAc) (5) have been determined. The coordination sphere around Tl³⁺ is a distorted square-based pyramid in which the apical site is occupied by a bidentate chelating OAc^- group for 3 and 5. The plane of three pyrrole nitrogen atoms (i.e., N(1), N(2) and N(3)), strongly bonded to Tl³⁺ in 3 and 5, is adopted as a reference plane, 3N. The porphyrin ring is severely distorted and the pyrrole ring N(4) bonding to the oxygen and NSO₂C₆H₄^tBu group makes a dihedral angle of 46.5° and 46.7° with the 3N plane for 3 and 5, respectively. In 3, Tl³⁺ and O(1) are located on the same side at 1.11 and 1.34 A? from its 3N plane, and in 5, Tl³⁺ and N(5) are also located on the same side at 1.15 and 1.30 A? from its 3N plane. The free energy of activation at the coalescence T_c for the intermolecular acetate exchange process of 3 and 5 in CD₂Cl₂ is found to be Δ G₁₈₄^? = 39.3 and Δ G₂₀₈^? = 44.1 kJ / mol, respectively, through ¹H NMR variable temperature measurements. An electronegative substituent, O(1), bonded to Tl in 3 causes a significant negative contribution up to 145 Hz for Δ³J(Tl-C, O) and 79 Hz for Δ²J(Tl-C, O) for OAc^- in 3.

Full text of DOI:10.1016/j.poly.2006.01.020

Polyhedron 25 (2006) 2207–2214
www.elsevier.com/locate/poly
Thallium complexes of tetraphenylporphyrin: Tl(tpp-N-O)(OAc)
and cis-acetato-N-p-tert-butylbenzensulfonylimido-meso-
t
tetraphenylporphyrinatothallium(III) Tl(N-p-NSO2C6H4 Bu-tpp)(OAc)
a
a
a,
b,
*
Fuh-An Yang , Kuan-Yu Cho , Jyh-Horung Chen *, Shin-Shin Wang
,
c
c
d
e
Jo-Yu Tung , Hsi-Ying Hsieh , Feng-Ling Liao , Gene-Hsiang Lee ,
f
g
Lian-Pin Hwang , Shanmugam Elango
a
Department of Chemistry, National Chung-Hsing University, Taichung 40227, Taiwan
b
Union Chemical Laboratories, Hsin-Chu 300, Taiwan
Chung Hwa College of Medical Technology, Tainan 717, Taiwan
c
d
Department of Chemistry, National Tsing-Hua University, Hsin-Chu 300, Taiwan
e
Instrumentation Center, National Taiwan University, Taiwan
Department of Chemistry, National Taiwan University and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10764, Taiwan
f
g
Institute of Chemical and Engineering Sciences, Singapore 627833, Singapore
Received 9 December 2005; accepted 10 January 2006
Available online 7 March 2006
Abstract
The crystal structures of Tl(tpp-N-O)(OAc) (3) and acetato-N-p-tert-butylbenzensulfonylimido-meso-tetraphenylporphyrinatothal-
lium(III) Tl(N-p-NSO2C6H4 Bu-tpp)(OAc) (5) have been determined. The coordination sphere around Tl3+ is a distorted square-based
t
pyramid in which the apical site is occupied by a bidentate chelating OAcꢀ group for 3 and 5. The plane of three pyrrole nitrogen atoms
(i.e., N(1), N(2) and N(3)), strongly bonded to Tl3+ in 3 and 5, is adopted as a reference plane, 3N. The porphyrin ring is severely dis-
t
torted and the pyrrole ring N(4) bonding to the oxygen and NSO2C6H4 Bu group makes a dihedral angle of 46.5ꢀ and 46.7ꢀ with the 3N
plane for 3 and 5, respectively. In 3, Tl3+ and O(1) are located on the same side at 1.11 and 1.34 A from its 3N plane, and in 5, Tl3+ and
˚
˚
N(5) are also located on the same side at 1.15 and 1.30 A from its 3N plane. The free energy of activation at the coalescence Tc for the
intermolecular acetate exchange process of 3 and 5 in CD2Cl2 is found to be DGz184 ¼ 39:3 and DG2z08 ¼ 44:1 kJ=mol, respectively,
1
through H NMR variable temperature measurements.
An electronegative substituent, O(1), bonded to Tl in 3 causes a significant negative contribution up to 145 Hz for D3J(Tl–C, O) and
79 Hz for D2J(Tl–C, O) for OAcꢀ in 3.
ꢁ 2006 Elsevier Ltd. All rights reserved.
Keywords: Thallium; X-ray diffraction; N-oxide; Torsion angle; Dynamic NMR
1. Introduction
[1]), metal–N–N linkage (metal = Zn [2–4], Ni [5,6], Fe
[3,7], Tl [5,8,9], Ga [8,9]) and metal–C–N linkage
(metal = Fe [10]) have been reported. Balch and coworkers
reported that the insertion of nickel(II) into H2(OEP-N-O)
(OEP = dianion of octaethylporphyrin) produced the com-
plex Ni(OEP-N-O) (1), in which the metal ions are bound
to a nearly planar set of three nitrogen atoms and one oxy-
gen atom [1,11]. Upon replacing OEP2ꢀ with tpp2ꢀ
(tpp = dianion of meso-tetraphenylporphyrin), the
Metalloporphyrins with a bridged structure between the
central metal and one of the four pyrrole nitrogens have
drawn much attention in recent times and so far bridged
metalloporphyrins with a metal–O–N linkage (metal = Ni
*
Corresponding authors.
E-mail address: JyhHChen@dragon.nchu.edu.tw (J.-H. Chen).
0277-5387/$ - see front matter ꢁ 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2006.01.020

2208
F.-A. Yang et al. / Polyhedron 25 (2006) 2207–2214
complex 1 became Ni(tpp-N-O) (2) [12]. However, until
now there has been no X-ray structural data available for
the diamagnetic and bridged metal [M(III)] porphyrin
complexes with an oxygen atom being inserted between
one metal–N unit and with a coordination number (CN)
above 4 (i.e., with CN = 5).
the porphyrin core and to the porphyrin substituents and
axial ligands. Many long-range Tl–C and Tl–H couplings
to the porphyrin substituents and to the axial ligands are
observed [16,17]. Moreover, there is no precedence in the
literature that the magnitude of two- and three-bond thal-
lium–carbon spin–spin coupling constants between the Tl
atom and the OAcꢀ group of 3 and 5 depends on the elec-
tronegative substituents X (i.e., X = O in 3 and N in 5)
attached to the thallium atom. Thus, the electronegative
dependence of spin–spin coupling constants nJ(Tl–13C)
(n = 2, 3) for the OAcꢀ ligand of 3 and 5 will be studied
for the first time in the chemistry of thallium porphyrins.
The compound 3 is the first thallium porphyrin complex
with a Tl–O–N(Por) linkage and 5 represents the fourth
thallium complex with a Tl–N(R)–N(Por) linkage reported
in the literature [5,8,9].
In order to investigate the range of metal ions that can
be inserted into H2(tpp-N-O), we present the results upon
replacing Ni(II) with Tl(III) in Ni(tpp-N-O) (2) forming a
new complex Tl(tpp-N-O)(OAc) (3). This replacement
increases the coordination number (CN) from four for 2
to six for Tl(tpp-N-O)(OAc) (3). The presence of acetate
ligands in 3 plays a potential role in increasing the coordi-
nation number.
In order to figure out the structural features of oxygen
and nitrogen inserted into the Tl–N bond, we also describe
the synthesis and X-ray structural investigation on the met-
allation of 21-(4-tert-butyl-benzensulfonamido)-5,10,15,
2. Experimental
t
20-tetraphenylporphyrin [N-p-HNSO2C6H4 Bu-Htpp (4)],
leading to the mononuclear complex cis-acetato-N-p-tert-
2.1. Tl(tpp-N-O)(OAc) (3)
butylbenzensulfonylimido-meso-tetraphenylporphyrinato-
t
thallium(III)
Tl(N-p-NSO2C6H4 Bu-tpp)(OAc)
(5).
A mixture of H2(tpp-N-O) (0.063 g, 0.1 mmol) in
CH2Cl2 (20 cm3) and Tl(OAc)3 (0.08 g, 0.2 mmol) in
MeOH (10 cm3) was refluxed for 3 h (Scheme 1) [12]. After
concentrating, the residue was redissolved in CH2Cl2, dried
with anhydrous Na2SO4, and filtered. The filtrate was con-
centrated and recrystallized from CH2Cl2–MeOH [1:2 (v/
v)] yielding the blue solid of 3 (0.062 g, 7 · 10ꢀ2 mmol,
70%). Compound 3 was dissolved in toluene to crystallize
Because of the large size of Tl3+ (rion = 1.025 A) [13] the rel-
ative position of acetate and the 4-tert-butylbenzensulfonyl
(tBuBS) group coordinated to the Tl atom might lead to a
cis configuration in 5 [5,8,9]. Prompted by earlier studies on
the acetato exchange of Tl(tpp)(OAc) and Tl(N-NTs-tpp)-
(OAc) in CD2Cl2(NTs = tosylimido) [8,14,15], we investi-
gated a similar intermolecular acetato exchange for 3 and
5 in CD2Cl2 by 1H and 13C dynamic NMR methods.
Thallium shows rich coupling patterns to the nuclei of
˚
1
out as blue crystals for single-crystal X-ray analysis. H
NMR (599.95 MHz, CDCl3, 20 ꢀC): d 9.18 [dd, 2H, Hb
O
O
N
Tl(OAc)3
N
Tl
N
N
Tl(tpp)(OAc)
O
O
O
N
N
N
(1) m-CPBA
(2) Tl(OAc)3
Tl
N
70%
H
H
N
N
N
N
Tl(tpp-N-O)(OAc)
(3)
Z
O
O
N
N
t
(1) p-C6H4 BuSO2-N3
70%
N
Tl
N
(2) Tl(OAc)3
N
t
Tl(N-p-SO2C6H4 Bu-tpp)(OAc)
(5)
N
N
H
t
=
H
N
H2tpp
;
;
p-SO2C6H4 Bu
m-CPBA = m-chloroperoxybenzoic acid
Z =
[12]
N
Scheme 1.

F.-A. Yang et al. / Polyhedron 25 (2006) 2207–2214
2209
(2, 13), 4J(Tl–H) = 13 Hz and 3J(H–H) = 4.8 Hz], Hb (a, b)
represents the 2 equiv. b-pyrrole protons attached to car-
bons a and b, respectively; 8.93 [dd, 2H, Hb (3, 12),
4J(Tl–H) = 20 Hz and 3J(H–H) = 4.8 Hz]; 8.79 [d, 2H,
Hb (7, 8), 4J(Tl–H) = 79 Hz]; 6.65 [s, 2H, Hb (17, 18)];
(NOE) difference spectroscopy was employed to determine
1
the H–1H proximity through space over a distance of up
˚
to about 4 A.
Positive ion mode ESI mass spectra were acquired at
room temperature on a ThermoFinnigan LCQ Advantage
mass spectrometer. The positive-ion fast atom bombard-
ment mass spectrum (FAB MS) was obtained in a nitrob-
enzyl alcohol (NBA) matrix using a JEOL JMS-SX/SX
102A mass spectrometer. UV/Vis spectra were recorded
at 20 ꢀC on a HITACHI U-3210 spectrophotometer.
3
8.45 [d, 2H, o-H (26, 28), J(H–H) = 4.4 Hz], o-H repre-
sents ortho phenyl protons; 8.07 [s, 2H, o-H (22, 32)];
7.72–7.81(m, 12H) for meta and para phenyl protons (m-,
p-H); 0.54 (s, 3H, OAc). FAB MS, m/z (assignment, rel.
intensity): 154 ([NBA + H]+, 100), 614 ([H2tpp]+, 36.31),
630 ([H2tpp-N-O]+, 40.13), 631 ([H2tpp-N-O + H]+,
42.67), 833 ([Tl(tpp-N-O)]+, 64.31), UV/Vis spectrum, k/
nm [e · 10ꢀ3 (Mꢀ1 cmꢀ1)] in CH2Cl2: 333.2 (17.1), 477.2
(173.0), 584.4 (9.1), 626.0 (10.9).
2.4. Crystallography
Table 1 presents the crystal data as well as other infor-
mation for 3 and 5. Measurements for 3 were taken on a
Nonius Kappa CCD diffractometer using monochroma-
t
2.2. Tl(N-p-NSO2C6H4 Bu-tpp)(OAc) (5)
˚
tized Mo Ka radiation (k = 0.71073 A) at a temperature
A mixture of Tl(OAc)3 (0.05 g, 1.31 · 10ꢀ4 mol) in
of 100(1) K. Measurements for 5 were taken on a Bruker
MeOH (20 cm3) and N-p-HNSO2C6H4 Bu-Htpp (0.05 g,
AXS SMART-1000 diffractometer using monochromatized
t
6.06 · 10ꢀ5 mol) in CH2Cl2 (50 cm3) was refluxed for 3 h
(Scheme 1) [9]. After concentrating, the residue was dis-
solved in CH2Cl2, dried with anhydrous Na2SO4, and fil-
tered. The filtrate was concentrated and recrystallized
from CH2Cl2–MeOH [1:3 (v/v)] yielding the bluish-purple
solid of 5 (0.046 g, 4.23 · 10ꢀ5 mol, 70%) which was again
dissolved in CH2Cl2 and layered with MeOH to get purple
crystals for single crystal X-ray analysis. 1H NMR
(299.95 MHz, CD2Cl2, 20 ꢀC): d 9.05 [dd, 2H, Hb
Mo Ka radiation (k = 0.71073 A) at a temperature of
˚
100(2) K. Muti-scan absorption corrections were made
for 3 and empirical absorption corrections were made for
5. The structures were solved by direct methods (SHELXL-
97) [18] and refined by the full-matrix least-squares
method. The OAc group within 3 is disordered with an
occupancy factor of 0.6 for O(2)O(3)C(45)C(46) and 0.4
for O(20)O(30)C(450)C(460). These four atoms (i.e., O(2),
O(3), C(45) and C(46)) were refined with isotropic displace-
ment parameters. All non-hydrogen atoms, except the
4
3
(10, 19), J(Tl–H) = 17.1 Hz and J(H–H) = 4.8 Hz]; 8.92
[dd, 2H, Hb (9, 20), 4J(Tl–H) = 10.4 Hz and 3J(H–
4
H) = 4.8 Hz]; 8.69 [d, 2H, Hb (4, 5), J(Tl–H) = 76.5 Hz];
Table 1
8.38 [d, 2H, 3J(H–H) = 7 Hz] and 8.10 [d, 2H, 3J(H–
H) = 7 Hz] for ortho protons; 7.85–7.76 (m, 12H, for meta
Crystal data for 3 Æ CH2Cl2 and 5
Empirical formula
Formula weight
Space group
C47H33Cl2N4O3Tl (3 Æ CH2Cl2) C56H44N5O4STl (5)
t
and para protons); 7.07 [d, 2H, BuBS-H3,5 or H (49, 51),
977.04
1087.39
P21/n
3J(H–H) = 8 Hz]; 6.94 [s, 2H, Hb (14, 15)], 6.09 [d, 2H,
ꢀ
P1
tBuBS-H2,6 or H (48, 52), J(H–H) = 8 Hz]; 1.15 (s, 9H,
3
Crystal system
triclinic
10.3685(4)
12.2132(4)
17.4671(6)
71.214(2)
77.251(2)
69.573(2)
1947.72(12)
2
monoclinic
12.9290(8)
24.4703(15)
14.9484(9)
90
102.981(1)
90
4608.5(5)
4
˚
a (A)
t-butyl protons); 0.62 (s, 3H, OAc). ESI–MS, m/z
˚
b (A)
t
(assignment, rel. intensity): 1087 ([Tl(N-p-NSO2C6H4 Bu-
˚
c (A)
t
tpp)(OAc)]+, 12.26), 1086 ([Tl(N-p-NSO2C6H4 Bu-
a (ꢀ)
b (ꢀ)
c (ꢀ)
t
tpp)(OAc)-H]+, 16.34), 1030 ([Tl(N-p-NSO2C6H4 Bu-
t
tpp) + 2 H]+, 100), 1028 ([Tl(N-p-NSO2C6H4 Bu-tpp)]+,
3
˚
74.18). UV/Vis spectrum, k/nm [e · 10ꢀ3 (Mꢀ1 cmꢀ1)] in
V (A )
Z
CH2Cl2: 332 (23.0), 446 (354), 555 (8.4), 609 (19.1).
F(000)
964
1.666
4.333
2176
1.567
3.605
Dcalcd (g cmꢀ3
)
l(Mo Ka) (mmꢀ1
)
2.3. Spectroscopy
S
1.088
0.959
0.50 · 0.41 · 0.12
56.68
100(2)
11415
Crystal size (mm3) 0.20 · 0.08 · 0.08
Proton and 13C NMR spectra were recorded at 299.95
(or 599.95) and 75.43 (or 150.87) MHz, respectively, on
Varian VXR-300 (or Varian Unity Inova-600) spectrome-
ters locked on deuterated solvent, and referenced to the sol-
vent peak. Proton NMR is relative to CD2Cl2 or CDCl3 at
d = 5.30 or 7.24 and 13C NMR to the center line of CD2Cl2
or CDCl3 at d = 53.6 or 77.0. HMQC (heteronuclear multi-
ple quantum coherence) was used to correlate protons and
carbon through one-bond coupling and HMBC (heteronu-
clear multiple bond coherence) for two- and three-bond
proton–carbon coupling. Nuclear Overhauser effect
2hmax (ꢀ)
T (K)
55.0
100(1)
8846
Number of
reflections
measured
Number of
reflections
observed
7605
9395 (I > 2r(I))
a
R1
wR2
0.0426
0.0987
0.0300
0.0699
b
P
P
a
R1 = [ iFo| ꢀ |Fci/ |Fo|].
P
P
2
2
1=2
b
wR2 ¼ f ½wðF 2o–F c2Þ ꢁ= ½wðF 2oÞ ꢁg
.

2210
F.-A. Yang et al. / Polyhedron 25 (2006) 2207–2214
Table 2
˚
Selected bond distances (A) and bond angles (ꢀ) for compounds 3 Æ CH2Cl2
and 5
3 Æ CH2Cl2
Bond lengths
Tl–O(2)
2.357(9)
Tl–O(3)
2.348(8)
Bond angles
O(2)–Tl–O(3)
O(2)–Tl–N(1)
O(2)–Tl–N(2)
O(2)–Tl–N(3)
O(2)–Tl–O(1)
N(1)–Tl–O(1)
N(1)–Tl–N(2)
N(3)–Tl–N(2)
55.2(4)
92.6(3)
O(1)–Tl–N(3)
O(3)–Tl–N(1)
O(3)–Tl–N(2)
O(3)–Tl–N(3)
O(3)–Tl–O(1)
O(3)–C(45)–O(2)
Tl–O(1)–N(4)
83.85(14)
147.7(3)
98.8(3)
100.0(3)
145.9(3)
103.1 (2)
87.51(14)
83.41(16)
81.53(16)
90.8(2)
101.0(2)
121.9(9)
106.2(3)
5
Bond lengths
Tl(1)–O(1)
2.337(2)
Tl(1)–O(2)
2.350(2)
Bond angles
O(1)–Tl(1)–O(2)
O(1)–Tl(1)–N(1)
O(1)–Tl(1)–N(2)
O(1)–Tl(1)–N(3)
O(1)–Tl(1)–N(5)
Tl(1)–N(5)–S(1)
Tl(1)–N(5)–N(4)
N(5)–Tl(1)–N(1)
55.85(7)
148.99(8)
100.86(9)
91.97(8)
102.91(8)
133.96(14)
109.36(17)
85.08(9)
O(2)–Tl(1)–N(1)
O(2)–Tl(1)–N(2)
O(2)–Tl(1)–N(3)
O(2)–Tl(1)–N(5)
Tl(1)–O(1)–C(45)
Tl(1)–O(2)–C(45)
O(1)–C(45)–O(2)
N(5)–Tl(1)–N(3)
93.26(8)
94.16(9)
145.97(8)
111.79(9)
91.60(18)
91.01(18)
121.5(3)
83.80(9)
above four atoms, were refined with anisotropic thermal
parameters, whereas all hydrogen atoms were placed in cal-
culated positions and refined with a riding model. Table 2
lists selected bond distances and bond angles for complexes
3 and 5.
3. Results and discussion
3.1. Molecular structures of 3 and 5
The X-ray molecules are depicted in Fig. 1a for the
complex Tl(tpp-N-O)(OAc) (3) and in Fig. 1b for
t
Tl(N-p-NSO2C6H4 Bu-tpp)(OAc)5. The complex 3 co-
Fig. 1. Molecular configuration and atom labelling scheme for (a) Tl(tpp-
N-O)(OAc) (3), (b) Tl(N-p-SO2C6H4 Bu-tpp)(OAc) (5), with ellipsoids
drawn at 50% probability for 3 and at 30% probability for 5. Hydrogen
atoms for all compounds are omitted for clarity.
recrystallizes with 1 equiv. of CH2Cl2 solvent molecule in
t
ꢀ
the triclinic space group P1, and complex 5 recrystallizes
in the monoclinic space group P21/n. In both 3 and 5, it
t
is obvious that the oxygen and NSO2C6H4 Bu moieties
have been inserted into the Tl–N bond of acetato(meso-
tetraphenylporphyrinato)thallium(III) Tl(tpp)(OAc) (see
Scheme 1) [15].
by a bidentate chelating OAcꢀ group for 3 and 5. Fig. 2
shows the actual porphyrin skeleton of 3 and 5. The pyr-
role nitrogens N(4) (in 3 and 5) are no longer bonded to
the thallium as indicated by their longer internuclear dis-
tances, 2.831(4) A for N(4)ꢂ ꢂ ꢂTl (in 3) and 2.899(2) A for
N(4)ꢂ ꢂ ꢂTl(1) (in 5). The plane of three strongly bound pyr-
role nitrogen atoms (i.e., N(1)–N(3) for 3 and 5) is adopted
as a reference plane 3N. It is noted that the ionic radius
The metal–ligand bond distances and the bond angles
˚
are summarized in Table 2. The bond distance (A) are
˚
˚
Tl–O(2) = 2.357(9), Tl–O(3) = 2.348(8) and Tl–O(1) =
2.126(4) and the mean Tl–N(p) = 2.264(4) for 3; for 5 the
values are Tl(1)–O(1) = 2.337(2) and Tl(1)–O(2) =
2.350(2) and the mean Tl(1)–N(p) = 2.241(2). Since the
acetate of 3 was disordered, data reported involving O(2)
and O(3) refer to the acetate at the higher occupancy factor
of 0.6.
2+
3+
˚
˚
increases from 0.63 A for Ni to 1.025 A for Tl [1,13].
Because of the larger size of Tl3+, Tl and O(1) lie 1.11
˚
and 1.34 A, respectively, above the 3N plane in 3, com-
pared to 1.15 A for Tl(1) and 1.30 A for N(5) in 5 (cf.
0.05 A for Ni(II) in Ni(OEP-N-O)) (Fig. 2) [1].
The geometry around Tl3+ is described as a distorted
square-based pyramid in which the apical site is occupied
˚
˚
˚

F.-A. Yang et al. / Polyhedron 25 (2006) 2207–2214
2211
Table 3
C(3)
0.23
C(2)
0.27
˚
Comparison of distances (A) and bond angles (ꢀ) in 3 and 5 with oxygen
and nitrogen units (X) inserted between one Tl–N unit
t
Parameters
X = O (3)
Parameters
X = NSO2C6H4 Bu (5)
0.04
0.10
0
3
5
-0.15
-0.16
N(1)
O(1)–Tl
N(1)–Tl
N(2)–Tl
N(3)–Tl
N(4)ꢂ ꢂ ꢂTl
N(4)–O(1)
2.126(4) Tl(1)–N(5)
2.306(4) Tl(1)–N(1)
2.150(4) Tl(1)–N(2)
2.335(4) Tl(1)–N(3)
2.831(4) Tl(1)ꢂ ꢂ ꢂN(4)
1.369(5) N(4)–N(5)
2.128(2)
2.320(2)
2.153(2)
2.364(2)
2.899(2)
1.386(3)
O(2)
3.02
O(1)
1.34
-0.43
-0.21
C(7)
-0.51
O(3)
3.15
C(18)
-1.44
N(4)
0.07
N(2)
0
O(1)–Tl–N(2) 155.45(16) N(5)–Tl(1)–N(2) 151.74(9)
N(1)–Tl–N(3) 121.28(15) N(3)–Tl(1)–N(1) 118.84(8)
Tl
1.11
C(8)
-0.42
C(17)
-1.54
-0.08
-0.58
occur with N(1), N(2) and N(3) pyrroles for compound 3
and 6.8ꢀ, 10.8ꢀ and 7.9ꢀ with N(1), N(2) and N(3) pyrroles
for compound 5. The dihedral angles between the mean
plane of the skeleton (3N) and the plane of the phenyl
group are 49.8ꢀ [C(24)], 53.1ꢀ [C(30)], 44.7ꢀ [C(36)] and
44.0ꢀ [C(42)] for 3 and the corresponding angles are
49.4ꢀ, 57.4ꢀ, 45.0ꢀ and 53.1ꢀ for 5.
N(3)
0
0.10
-0.44
0.17
-0.04
C(13)
0.17
C(12)
0.33
Table 3 contains some comparative data. The N(4)–O(1)
˚
(a) Tl(tpp-N-O)(OAc) 3
distance of 1.369(5) A in 3 is comparable to that in
˚
Ni(OEP-N-O) [1.363(6) A] [1]. The trans O(1)–Tl–N(2)
C(10)
C(9)
and N(1)–Tl–N(3) angles [155.45(16)ꢀ and 121.28(15)ꢀ] in
3 and the corresponding N(5)–Tl(1)–N(2) and N(1)–
Tl(1)–N(3) angles [151.74(9)ꢀ and 118.84(8)ꢀ] in 5 indicate
that both complexes are severely distorted from linearity.
In compound 3, such a large deviation from planarity
for the N(4) pyrrole is also reflected by observing a 19–
22 ppm upfield shift of the Cb (C17, C18) at 112.9 ppm
compared to 135.2 ppm for Cb (C2, C13), 133.7 ppm for
Cb (C3, C12) and 131.8 ppm for Cb (C7, C8). In compound
5, a similar deviation is also found for the N(4) pyrrole by
observing a 16–21 ppm upfield shift of the Cb (C14, C15) at
115.7 ppm compared to 136.4 for Cb (C10, C19),
133.7 ppm for Cb (C9, C20) and 132.2 ppm for Cb (C4,
C5). Similarly, the non-planarity of the porphyrins causing
upfield shifts of Cb resonances were also observed with a
magnitude of 16–21 ppm for Tl(N-NTs-tpp)(OAc) [8].
0.15
0.28
0.15
-0.05
0
N(3)
-0.43
-0.60
0.04
2.55
3.09
O(1)
-0.09
C(5)
-0.37
C(14)
N(5)
O(2)
-1.55
1.30
2.99
N(4)
N(2)
0
Tl(1)
C(4)
-0.40
0.03
C(15)
1.15
-1.49
-0.51
-0.25
-0.14
N(1)
-0.03
0
0.05
0.09
3.2. H and 13C NMR for 3 and 5 in CD2Cl2 and CDCl3
1
C(19)
C(20)
0.25
0.25
1
Complexes 3 and 5 were characterized by H (Fig. 3)
t
and 13C NMR analysis. In solution, the molecules have
effective Cs symmetry with a mirror plane running through
the N(2)–Tl–O(1)–N(4) unit for 3 and the N(2)–Tl(1)–
N(4)–N(5) unit for 5. There are four distinct b-pyrrole pro-
tons Hb, four b-pyrrole carbons Cb, four a-pyrrole carbons
Ca, two different meso carbons Cmeso and two phenyl-C1
carbons for both the complexes.
(b) Tl(N-p-NSO2C6H4 Bu-tpp)(OAc) 5
Fig. 2. Diagram of the porphyrinato core (C20N4, M, O, tBuBS and
OAcꢀ) of (a) 3 Æ CH2Cl2 and (b) 5. The values represent the displacements
(in angstroms) of the atoms from the mean 3N plane (i.e., N(1)–N(3) for
3 Æ CH2Cl2 and 5).
The porphyrin macrocycle is indeed distorted because of
the presence of the oxygen [O(1)] and the NSO2C6H4 Bu
The NMR study of 3 showed four different types of Tl–H
coupling constants for Hb in CD2Cl2 at 20 ꢀC (Fig. 3a). The
t
4
group in 3 and 5, respectively (Fig. 2). Thus, N(4) in the
3 and 5 pyrrole rings bearing the oxygen and the
doublet at 8.70 ppm is assigned as Hb (7, 8) with J(Tl–
H) = 78 Hz and the singlet at 6.64 ppm is due to Hb
(17, 18). The doublet of a doublets at 9.18 ppm is due to
t
NSO2C6H4 Bu group is deviated most from the 3N plane
4
3
and oriented separately with a dihedral angle of 47.3ꢀ
and of 46.7ꢀ, whereas small angles of 7.0ꢀ, 13.1ꢀ and 9.0ꢀ
Hb (2, 13) with J(Tl–H) = 14 Hz and J(H–H) = 4.2 Hz
and the doublet of a doublets at 8.93 ppm is due to Hb

2212
F.-A. Yang et al. / Polyhedron 25 (2006) 2207–2214
Hb (14, 15). The doublet of a doublets at 9.05 ppm is due
to Hb (10, 19) with 4J(Tl–H) = 17.1 Hz and 3J(H–H)
= 4.8 Hz and the doublet of a doublets at 8.92 ppm is
4
3
due to Hb (9, 20) with J(Tl–H) = 10.4 Hz and J(H–H)
= 4.8 Hz. Likewise, there were also four different types of
Tl–13C coupling constants for Cb 5 in CD2Cl2 at 20 ꢀC.
The doublet at 132.2 ppm is due to Cb (C4, C5) with
3J(Tl–13C) = 165 Hz and the doublet at 136.4 ppm is due
3
to Cb (C10, C19) with J(Tl–13C) = 37 Hz. The singlet at
133.7 ppm supposedly due to Cb (C9, C20) with
3J(Tl–13C) is not observed and the doublet at 115.7 ppm
4
1
is due to Cb (C14, C15) with J(Tl–13C) = 78 Hz. The H
NMR spectra reveal that the aromatic protons of the
tBuBS group appear as a doublet at 6.94 (tBuBS-H3,5
)
and a doublet at 6.09 ppm (tBuBS-H2,6) for 5. Due to the
t
porphyrin ring current effect, all NSO2C6H4 Bu and ace-
tato protons are shifted upfield compared to their counter-
parts in free NSO2C6H4 Bu and OAcꢀ. The above ring
t
t
current effect indicates that both the NSO2C6H4 Bu and
acetate ligands are bonded to Tl in 5 in the solution phase.
t
The NSO2C6H4 Bu bonding argument is further confirmed
t
by the result that the BuBS–C1 (i.e., C(47)) peak in 5 was
observed at 137.6 ppm with 3J(Tl–C) = 46 Hz. X-ray
diffraction analysis unambiguously confirms that 5 is a
bidentate complex in the solid phase.
Fig. 3 depicts representative 1H spectra for 3 in CD2Cl2 at
20 and ꢀ90 ꢀC. At 20 ꢀC, the rotation of the phenyl group
along the C1–Cmeso [C(5)–C(21) or C(10)–C(27)] bond is
intermediately slow [19]. This intermediately slow rotation
is supported by the two broad singlets at 8.36 and
8.10 ppm for the ortho protons o-H (26, 28) and o-H
(22, 32), respectively. Moreover, the rotation of the phenyl
group along the C(15)–C(33) [or C(20)–C(39)] bond is at
the intermediate exchange region [21]. In this intermediate
exchange region, the signals are broadened beyond detec-
tion. Hence, no signals of o0-H (34, 44) and o0-H (38, 40)
have been found at 20 ꢀC (Fig. 3a). At ꢀ90 ꢀC, this rotation
is extremely slow. Hence, the rate of intramolecular
exchange of the ortho protons for 3 in CD2Cl2 is also extre-
mely slow. The singlet at 8.85 ppm is assigned to ortho pro-
tons o0-H (38, 40) (Fig. 3b). The other singlet at 8.05 ppm is
due to ortho protons o0-H (34, 44). Likewise, the singlet at
8.45 ppm is due to the ortho protons o-H (26, 28) and singlet
at 8.13 ppm is due to the ortho protons o0-H (22, 32)
(Fig. 3b). In a similar way, the meta and para protons
appearing as multiplet (7.76–7.84 ppm) at 20 ꢀC (Fig. 3a)
changed to 7.94 [t, m0-H (37, 41)], 7.86 [t, m-H (25, 29)],
7.82 [m, m0-H (35, 43)], 7.81 [m, p0-H (36, 42)] and 7.80 [m,
m-H (23, 31) and p-H (24, 30)] ppm at ꢀ90 ꢀC (Fig. 3b).
The interpretation of these data was confirmed by NOE dif-
ference spectroscopy for 3 in CD2Cl2 at 20 and ꢀ90 ꢀC.
In a similar fashion, the rotation for the phenyl group of 5
in CD2Cl2 at 20 ꢀC along the C(2)–C(21) [or C(7)–C(27)]
bond is slow and that rotation along C(12)–C(33) [or
Fig. 3. 1H NMR spectra for Tl(tpp-N-O)(OAc) at 599.95 MHz in CD2Cl2
showing four different b-pyrrole protons Hb and phenyl protons (o-H, m,
p-H): (a) 20 ꢀC; (b) ꢀ90 ꢀC.
(3, 12) with 4J(Tl–H) = 20 Hz and 3J(H–H) = 4.2 Hz. Like-
wise, there were also four different types of Tl–13C coupling
constants for Cb 3 in CDCl3 at 20 ꢀC. The doublet at
3
131.8 ppm is due to Cb (C7, C8) with J(Tl–13C) = 156 Hz
and the singlet at 133.7 ppm is due to Cb (C3, C12). The
doublet at 135.2 ppm is due to Cb (C2, C13) with
3J(Tl–13C) = 44 Hz and the doublet at 112.9 ppm is due
4
to Cb (C17, C18) with J(Tl–13C) = 80 Hz.
The NMR study of 5 showed four different types of
Tl–H coupling constants for Hb in CD2Cl2 at 20 ꢀC. The
doublet at 8.69 ppm is assigned as Hb (4, 5) with
4J(Tl–H) = 76.5 Hz and the singlet at 6.94 ppm is due to
1
C(17)–C(39)] is at the intermediate region. Hence, the H
resonances for the ortho protons of 5 were observed with
two sets of doublets: one doublet at 8.38 ppm is assigned

F.-A. Yang et al. / Polyhedron 25 (2006) 2207–2214
2213
3
to ortho protons o-H (26, 28) with 3J(H–H) = 7 Hz and the
other doublet at 8.10 ppm is due to ortho protons o-H
the Karplus-type dependence of J(Tl–C) on the torsion
angle UTla–Cd(Tla–Ob–Cc–13Cd) [21–23]. Hence, the com-
3
3
(22, 32) with J(H–H) = 7 Hz. Moreover, no signals of o0-
plexity of the J(Tl–C) coupling is primarily due to the
H (38, 40) and o0-H (34, 44) of 5 have been detected at 20 ꢀC.
3.3. Dynamic NMR of 3 and 5 in CD2Cl2
angular dependence on U and also due to the substituent
effects arising from the nature, position and orientation.
The substituents (X) bonded to the coupled Tla thallium
induces an additional angular dependence on the torsion
angle WX–Cc(X–Tla–Ob–Cc). Experimentally, the depen-
Upon cooling of a 0.02 M CD2Cl2 solution of 3, the
methyl proton signal of OAcꢀ, being a single peak at
20 ꢀC (d = 0.45 ppm), first broadened (coalescence temper-
ature Tc = ꢀ89 ꢀC) and then split into two peaks with a
separation of 12 Hz at d = 0.35 ppm at ꢀ100 ꢀC. As the
exchange of OAcꢀ within 3 is reversible, the results at
599.95 MHz confirm the separation as a coupling of 4J
(Tl–H) rather than a chemical shift difference. The most
likely cause of loss of coupling is due to the reversible dis-
sociation of acetate with a small dissociation constant.
3
dence of the J(Tl–C) coupling on the torsion angles U,
W and electronegativity (v) for 3 and 5 is shown in Table
4. Analytically, the effect upon nJ(Tl–C) (n = 2, 3) of a sub-
stituent X (X = O, N) attached to a thallium atom is
defined by the difference DnJ(Tl–C, X) = nJ(Tl–C,
X)–nJ(Tl–C, P), where nJ(Tl–C, X) and nJ(Tl–C, P) are
the nJ(Tl–C) coupling for the X-monosubstituted
Tl(tpp)(OAc) and for the parent molecule of Tl(tpp)(OAc),
respectively [21]. In Table 4, the coupling constants from
our study and the published ones for thallium porphyrin
derivatives are provided for a comparison of the experi-
mental DnJ(Tl–C, X) values [5,8,14]. A maximum positive
contribution to 3J(Tl–C) is expected in the transoid
arrangement (U = 180ꢀ and W = 180ꢀ). The absolute values
of U and W are observed to be approximately constant
around 180ꢀ and 80.1 6.8ꢀ for complexes 3, 5 and their
homologue, respectively (Table 4), therefore the magnitude
of 3J(Tl–C) in the system X–Tla–Ob–Cc–13Cd shows a
strong dependence on the electronegativity (v) of the sub-
O
O
CD2Cl2
Tl(tpp-N-O) + OAc
ð1Þ
Tl
3
Such a scenario would lead to the change in the chemical
shift with temperature and no detectable free OAcꢀ and
Tl(tpp-N-O)+ at low temperature, but would lead to the loss
of coupling between acetate and thallium at higher temper-
ature [20]. The chemical shift in the high-temperature limit
is the average of the two species (i.e., Tl(tpp-N-O)(OAc) and
OAcꢀ) in Eq. (1) weighted by their concentration. The free
energy of activation DGz184 ¼ 39:3 kJ=mol is therefore deter-
mined for the intermolecular exchange of OAcꢀ in 3. The
free energy of activation at the coalescence temperature Tc
for a similar OAcꢀ exchange of 5 in CD2Cl2 is determined
to be DGz208 ¼ 44:1 kJ=mol. At 20 ꢀC, intermolecular ex-
change of the OAcꢀ group for 3 is rapid as indicated by
the appearance of singlet signals due to carbonyl carbons
at 175.8 ppm and methyl carbons at 18.9 ppm. At
ꢀ100 ꢀC, the rate of intermolecular exchange of OAcꢀ for
3 in CD2Cl2 is slow. Hence, at this temperature, the methyl
and carbonyl carbons of OAcꢀ are observed at d 18.5 ppm
[with 3J(Tl–C) = 135 Hz] and 176.0 ppm [with 2J(Tl–
C) = 156 Hz] as doublets, respectively. These 13C reso-
nances are quite close to that of 5 in which the two corre-
sponding carbons were observed in CD2Cl2 at d 18.6 ppm
[with 3J(Tl–C) = 221 Hz] and 176.4 ppm [with 2J(Tl–
C) = 205 Hz] as doublets at ꢀ90 ꢀC, but with different
2,3J(Tl–C) coupling constants. The bulky tBu group in 5 in-
creases the free energy of activation for the intermolecular
stituent X.
A
large negative value of D3J(Tl–C,
O) = ꢀ145 Hz is observed for 3 while a small negative val-
ues of D3J(Tl–C, N) = ꢀ57 3 Hz are assessed for 5, 6 and
7 (Table 4) [5,8]. Likewise, the magnitude of the geminal
thallium–carbon coupling constant, 2J(Tl–C), for the
OAcꢀ of 3 and 5 in the system X–Tla–Ob–13Cc depends
on the electronegativity (v) of X (Table 4). Experimentally,
a large negative value of D2J(Tl–C, O) = ꢀ79 Hz is
observed for 3 while a small negative value of D2J(Tl–C,
N) = ꢀ28 3 Hz is calculated for 5, 6 and 7 (Table 4)
[5,8]. Owing to the magnitude of DnJ(Tl–C, X) (n = 2, 3)
increasing with increasing electronegativity of X, the
t
smaller electronegativity of N(5)–SO2C6H4 Bu (with v
[N(5) = 2.98]) for
5 than the O(1) atom (with v
[O(1) = 3.44]) for 3 [24,25] results in the magnitude of
|D3J(Tl–C, N)| = 59 Hz in 5 being smaller than that of
|D3J(Tl–C, O)| = 145 Hz in 3 (Table 4). In a similar case,
the absolute value of |D2J(Tl–C, N)| = 30 Hz in 5 is smaller
than that of |D2J(Tl–C, O)| = 79 Hz in 3 (Table 4).
4. Conclusions
OAcꢀ exchange in CD2Cl2 from DGz ¼ 36:0 kJ=mol for
171
Tl(N-NTs-tpp)(OAc) to DGz208 ¼ 44:1 kJ=mol for 5 [8].
3.4. O(1) and N(5) atoms connected to a-thallium
The effect of a different electronegative atom O(1) [or
We have investigated two new diamagnetic and mono-
nuclear thallium(III) porphyrin complexes 3 and 5 and
their X-ray structures are established. NOE difference spec-
troscopies, HMQC and HMBC were employed for the
1
unambiguous assignment of the H and 13C NMR reso-
2
N(5)] attached to the thallium(III) in 3 (or 5) on J(Tl–C)
nances of 3 and 5 in CDCl3 at 20 ꢀC and in CD2Cl2 at 20
and ꢀ90 ꢀC. In brief, the electronegativity (v) of the X
atom attached to the a-thallium nucleus correlates to the
3
and J(Tl–C) of the OAcꢀ ligand was studied. The impor-
tance of the thallium carbon coupling comes mainly from

2214
F.-A. Yang et al. / Polyhedron 25 (2006) 2207–2214
Table 4
n
Effect of a-oxygen and nitrogen substituents on J(Tl–C) (n = 2, 3) for the OAcꢀ group of Tl(tpp-N-O)(OAc), 3, 5 and thallium porphyrin complexes in
CD2Cl2 at low temperaturea
Compounds
OAc
OAc
U (ꢀ)c
W (ꢀ)d
v (N)e
CH3 3J(Tl–C)
D3J(Tl–C, X) (Hz)b
CO2J(Tl–C)
D2J(Tl–C, X) (Hz)b
Tl(tpp)(OAc)14 (ꢀ90 ꢀC)
280
135
221
235
156
205
Tl(tpp-N-O)(OAc) (3) (ꢀ100 ꢀC)
ꢀ145
ꢀ59
ꢀ79
ꢀ30
ꢀ178.9
ꢀ175.2
82.9
73.3
3.44
2.98
t
Tl(N-p-NSO2C6H4 Bu-tpp)(OAc) (5)
(ꢀ90 ꢀC)
Tl(N-NTs-tpp)(OAc)8 (6) (ꢀ110 ꢀC)
Tl(N-p-NCOC6H4NO2-tpp)(OAc)5 (7)
(in THF-d8, ꢀ110 ꢀC)
220
227
ꢀ60
ꢀ53
205
211
ꢀ30
ꢀ24
178.5
176.6
ꢀ86.2
2.98
2.89
78.1
a
Measured in CD2Cl2 unless specified.
DnJ(Tl–C, X) = nJ(Tl–C, X)–nJ(Tl–C, P) (n = 2, 3 and X = O, N), where nJ(Tl–C, X) and nJ(Tl–C, P) are the nJ(Tl–C) coupling for the X-mono-
b
substituted Tl(tpp)(OAc) and for the parent molecule of Tl(tpp)(OAc).
c
The torsion angle U(Tla–Ob–Cc–13Cd) is the dihedral angle between coupled atoms Tla and Cd.
d
The torsion angle w(X–Tla–Ob–13Cc) is the dihedral angle between Cc and electronegative X.
e
Pauling scale value calculated by electronegativity equalisation, where N = O for 3, N–tBuBs for 5, N–NTs for 6 and NCOC6H4NO2 for 7 [24].
magnitude of the D2,3J (Tl–C, X) coupling for the
Tl(O2CCH3) fragment in the thallium porphyrin system.
The two compounds, despite the different electronic and
steric properties for O(1) in 3, and for the N-imido-benzen-
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Acknowledgement
The financial support from the National Science Council
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1
Fig. S1 shows the H NMR spectrum of 5 in CD2Cl2 at
20 ꢀC. Figs. S2 and S3 show the HMQC and HMBC spec-
tra of 3 in CD2Cl2 at 20 ꢀC. CCDC 288278 (for 3) and
CCDC 261305 (for 5) contain the supplementary crystallo-
graphic data for this paper. Copies of this information may
be obtained free of charge from The Director, CCDC, 12
Union Road, Cambridge, CB2 1EZ, UK on request (fax:
+44 1223 336 033; e-mail deposit@ccdc.cam.ac.uk or
www: http://www.ccdc.cam.ac.uk). Supplementary data
associated with this article can be found, in the online ver-
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